pg_escape_string

(PHP 4 >= 4.2.0, PHP 5, PHP 7)

pg_escape_string —
Escape a string for query

Description

stringpg_escape_string
([ resource$connection
], string$data
)

pg_escape_string() escapes a string for querying
the database. It returns an escaped string in the PostgreSQL
format without quotes. pg_escape_literal() is
more preferred way to escape SQL parameters for PostgreSQL.
addslashes() must not be used with PostgreSQL.
If the type of the column is
bytea, pg_escape_bytea() must be used
instead. pg_escape_identifier() must be used to
escape identifiers (e.g. table names, field names)

Note:

This function requires PostgreSQL 7.2 or later.

Parameters

connection

PostgreSQL database connection resource. When
connection is not present, the default connection
is used. The default connection is the last connection made by
pg_connect() or pg_pconnect().

See Also

User Contributed Notes 11 notes

Forthose curious, the exact escaping performed on the string may vary slightly depending on your database configuration.

For example, if your database's standard_conforming_strings variable is OFF, backslashes are treated as a special character and pg_escape_string() will ensure they are properly escaped. If this variable is ON, backslashes will be treated as ordinary characters, and pg_escape_string() will leave them as-is. In either case, the behavior matches the configuration of the database connection.

You should not need to change text encodings when using this function. Make sure your connection's client_encoding is set to the text encoding used by PHP, and the PostgreSQL client driver will take care of text encodings for you. No explicit utf-8 conversions should be necessary with a correctly set client_encoding.

Creating a double-tick is just fine. It works the same as the backslash-tick syntax. From the PostgreSQL docs:

The fact that string constants are bound by single quotes presents an obvious semantic problem, however, in that if the sequence itself contains a single quote, the literal bounds of the constant are made ambiguous. To escape (make literal) a single quote within the string, you may type two adjacent single quotes. The parser will interpret the two adjacent single quotes within the string constant as a single, literal single quote. PostgreSQL will also allow single quotes to be embedded by using a C-style backslash.

Please, as a service to the Internet, add a note advising developers to use prepared statements and placeholders, and deprecate this function and its friends (but not pg_escape_identifier).There is no valid reason to mix data and SQL into a single string before sending it to the RDBMS, and thus create the potential for SQL injection vulnerabilities. Hence, there is no need to escape data. Hence, there is no need for this function. It's confusing to offer developers functionality that they don't need and shouldn't use.

Since php 5.1 the new function pg_query_params() was introduced. With this function you can use bind variables and don't have to escape strings. If you can use it, do so. If unsure why, check the changelog for Postgres 8.0.8.

PostgreSQL is a powerful and an open source object relational database having more than 15 years of active development and a proven architecture with an emphasis on extensibility and standards compliance. PostgreSQL primary functions are to store data securely and return that data in response to requests from other software applications that has earned it a strong reputation for reliability, data integrity and correctness which runs on all major operating system including Linux, UNIX and Windows. PostgreSQL is a cross platform which is open source and its source code is available free of charge that is not controlled by any corporation or other private entity. PostgreSQL also supports storage of binary large objects including picture, sound or video along with handles workloads ranging from small single machine applications to large internet facing applications with lots of concurrent users­. PostgreSQL is highly scalable in the sheer quantity of data which support international character sets and multibyte character encodings.if you know more aboutthis note then please visit on our website.https://www.codesroom.com/blog/postgresql

For those who escape their single quotes with a backslash (ie \') instead of two single quotes in a row (ie '') there has recently been a SERIOUS sql injection vulnerability that can be employed taking advantage of your chosen escaping method. More info here: http://www.postgresql.org/docs/techdocs.50Even after the postgre update, you may still be limited to what you can do with your queries if you still insist on backslash escaping. It's a lesson to always use the PHP functions to do proper escaping instead of adhoc addslashes or magic quotes escaping.

This may seem obvious, but remember that pg_escape_string escapes values for use as string literals in an SQL query -- if you need to escape arbitrary strings for use as SQL identifiers (column names, etc.), there doesn't seem to be a PHP function for that so you'll have to do that escaping yourself. (PostgreSQL has an in-database function, quote_ident(), that does this.)

This can be an issue if your database contains mixed-case (or otherwise unusual) column names and you have a class interface managing your database/query interactions (for connecting to different types of databases). If you don't double-quote your column names then postgreSQL will match them case-insensitively, but will label the results in all-lowercase (which differs from MySQL).